What to Do If a Belt Is Slipping on a Scooter?

Both gas and electric scooters are great alternatives for those interested either in personal transportation or handicap mobility. These versatile machines offer the convenience of a bicycle with the speed and ease of a moped. Many gas scooters use some sort of belt drive, which is quieter, lighter and nearly as efficient as a chain drive. These belts will eventually begin to wear and slip, though, which is where the necessity for a little basic maintenance comes in.

Clean and Dry

The primary cause of belt slippage on any scooter is the presence of water, oil or grease on the belt. Some designs are more prone to this condition than others; the exhaust of a two-stroke engine is full of vaporized oil, which can build up and collect on the belt and pulley surfaces. Remove the belt from the pulleys, and clean the pulleys and surrounding area with a spray can of either carburetor or brake cleaner, then scuff the pulleys with some 180-grit sandpaper. Clean both the pulleys and belt with soapy water. After thoroughly drying the cleaned area, re-install the belt and check for squealing noise.

Tensioning and Dressing

If the belt is still squealing, adjust the tensioner, if you have one. The belt should deflect no more than 1/2-inch in the center of the longest stretch. The tensioner pulley is usually located on the bottom side of the belt, and will adjust in or out via a threaded collar. Turn the collar clockwise to increase tension, or counter-clockwise to decrease tension. If the pulley is adjusted as far as it will go and you can still deflect the belt more than 1/2-inch, then the tensioner may be worn out and needs replacement.

If the belt belt still squeals while tension is where it needs to be, try applying a belt dressing like those manufactured by Gunk. Belt dressings act like a sort of glue, and can significantly decrease belt slippage.

Replacement

If you've cleaned the pulleys, adjusted the tension and applied belt dressing and your belt still slips, then you need a new one. Consider an upgraded belt with Kevlar reinforcement and a stickier rubber compound. This is especially important on scooters equipped with CVT (Continuously Variable Transmission). Though pricey, a $100 Kevlar-reinforced belt will hold up a lot better under the extreme heating and stretching stresses encountered with these drive-trains.

Heavier riders equipped with non-CVT belt drives may need to be outfitted with a toothed-belt system. Toothed belts require matching gear-like pulleys, but offer power transfer unsurpassed by anything short of chains. A toothed system will typically out-last a smooth belt system, and will give high-powered scooters the ability to charge up steep grades without any possibility of slippage.